The Research Of Hydrodynamic Mechanism Of Formation Collapse And Interaction Between Free Surface Of Surface Of Supercavitation In The Process Of Water Exit Of A Vertically Launched Underwater Vehicle

The supercavitation technology has been attached importance to many countries in theresearch and applied of aerial body drag reduction, and there are lots of achievement has beenachieved. The problem of supercavitation vertical water of underwater navigation body is a bigdeal in the part of supercavitation technology, it has important applications in improving theoperational performance of underwater submarine-launched missiles. While the supercavitationof underwater navigation body always accompanied with multiphase flow、cavitations、phasetransitions、instability turbulence and other complex phenomena. The force which navigationbody suffered tend to strong unsteady、nonlinear and the literature research about this aspect isnot much no matter at home or abroad. So based on this background, this paper to the process ofthe supper bubble formed、 collapsed and the horizontal interactions of the hydrodynamicmechanism to have a deep research.Through combination experimental and numerical simulation to the process ofsupercavitation of navigation out of the water have a study. The experimental research study onthe basis of existing experimental laboratory then designed and processed different head shapeand aspect ratio of the navigation body model, the navigation body out of the water images werecaptured by high speed camera to realized the water flow of supercavitation visualization. Byconducting experiments with different navigation body, the stability of the water flow ofsupercavitation were obtained, and the reason of water flow instability was also analyzed.Through study found that the stability of the small aspect ratio navigation body is poor than thelarge aspect ratio one. The disk-type navigation body spect ratio above8(including flat and table-heaed type) can formed a stable water trajectory, the stability with cone angle navigation body isworse, and with dome is worst. Through calculate of different navigation body got the law of thewater flow process displacement、variation speed、cavitation number and drag coefficient ofthe flow parameters etc, given the fitting formula of the drag coefficient variation with different cavitation number and analyzed the variation law of the drag coefficient with different cavitationnumber. Measured the outline dimensions of the bubbles, studied the dimensionless bubble sizevariations with different cavitation number and the cavitation outline under different cavitationnumber, and compared with previous theoretical formula, it found that the experimental resultand theoretical formula fit well, in addition to studied the morphological changes of thesupercavitation from generation to collapsed, it also found that free surface to the bubblemorphology and collapsed effect, which compared theoretical formula of bubble collapsed timeturn out is right.The ANSYS FLUENT14.0was adopt when simulated the whole process of the water flowof the navigation body, to the underwater supercavitation run of the navigation body flow fieldhave an analyzed, studied the variation of the suppercavitation forms, when compared the resultof simulated and experimental is fit well, which lay the foundation for for future navigation bodysimulated.